MEDICO LEGAL M A G A Z I N E
GAIT ANALYSIS FOR ASSESSMENT OF LOWER LIMB FUNCTION AFTER INJURY OR SURGERY By Mr Trevor Prior BScHons, FCPod(s), FCPM Trevor Prior is a Consultant Podiatric Surgeon, Senior Clinical lecturer and Director of Premier Podiatry, specialising in foot surgery, sports injuries, biomechanics/gait analysis, orthoses and diabetic foot complications.
One of the challenges for assessing function of the foot and lower limb, especially in medico-legal examinations, is determining normal function. What has become clear within the scientific literature is that each of the joints within the foot demonstrates motion in all three body planes and that the amount and direction of motion shows great variability between individuals1. In addition, walking is not determined by foot structure and function alone, with the role of the hip and pelvis in driving foot function becoming increasingly apparent2. This clearly has implications for assessing function of the foot, ankle, leg, knee, hip and pelvis. Commonly, visual analysis is used as a simple clinical tool but remains subjective. Video analysis allows a more detailed evaluation and whilst some basic measures can be taken, reliability remains low and it is not possible to assess rotations of the leg, hip, knee and ankle.
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Traditionally, more advanced techniques have been the remit of sophisticated gait laboratories but are now increasingly available in the clinical environment. The use of a force platform, or insoles with force sensors, allows the assessment of the forces underneath the foot and is particularly helpful for assessing the impact of injury and surgery to the lower limb on foot function. For instance, the impact of an arthritic joint, a joint fusion or prosthesis on foot loading can be accurately assessed3. Whilst this does provide objective information relating to the force and pressure beneath the foot, there is still some subjectivity in interpretation. Click this link for an example case of a patient with an arthritic big toe. The use of reflective markers, which can be tracked by infra-red camera (similar to the technology used for animation in Hollywood), allows extremely accurate and highly reliable assessment of the function of the pelvis, hips, knees and ankle. This allows assessment
